Supplementary eye field

He noted that unilateral electrical stimulation of the frontal lobe of macaque monkeys caused "turning of the eyes and head to the opposite side" (Fig.

[11][12] As Penfield had noted the induction of gaze shifts by stimulation of the rostral part of the SMA, another eye field's existence was postulated.

In 1987, the SEF was finally characterized by Schlag and Schlag-Rey as an area where low intensity electrical stimulation could evoke saccades, similar to the FEF.

[1] The eye field originally defined by Ferrier's map of the frontal cortex extended medially to the dorsal surface of the brain (Fig.

[10] Experimenters have since established that the FEF and SEF are two separate and distinct brain areas responsible for saccade initiation through cerebral blood flow, and subdural electrode array studies.

[17] Based on single unit recording and microstimulation it has been established that the SEF is caudally contiguous with the parts of the SMA which represent orofacial, and forelimb movements.

[3] In this kind of task a trained monkey is to make a particular response (in this case move its eyes, or produce a saccade) to a stimulus on a screen such as a flashing dot.

[2][3] It can be thought that the FEF does the driving part of saccade initiation, while the SEF acts as a backseat passenger, advising the driver as to what to do based on past insights.

[23][24][25] This sudden shift can be a distraction but it has been also thought to be a reflex of great importance as identifying and reacting to environmental changes quickly (when needed) can be imperative to survival.

In this fashion, spike and local field potential (LFP) data can be acquired from SEF neurons, using microelectrodes in the recording chamber.

[2] Experiments obviously vary, but to give an example: the monkey might be made to partake in a color visual search task, sitting in front of a computer screen.

Figure 1. Motor Cortex of the Monkey Brain : Pictured above are the approximate locations of the SEF and FEF in the monkey brain which we know today.
Figure 2. Ferrier's Monkey Brain Map (1874). The highlighted area labeled 'EF' is the area he observed to cause eye and head movements when electrically stimulated. [ 9 ]
Figure 3. Brodmann Brain Map : The SEF is located in the rostral supplementary motor area which corresponds to Area 6 in the above map. For reference, the FEF is located in Area 8.